The present invention relates to a sole assembly. More particularly, the invention relates to the improvement of the sole construction, which is comprised of a midsole, a corrugated sheet, and an outsole.
The sole of an athletic shoe used for various sports is generally comprised of a midsole and an outsole. The midsole is typically formed of soft elastic material in order to ensure adequate cushioning properties. The outsole is fitted under the midsole and directly contacts with the ground.
Running stability as well as adequate cushioning properties is required in athletic shoes. There is need to prevent shoes from being deformed excessively in the lateral or transverse direction when contacting with the ground.
As shown in Japanese patent application publication No. 11-332606, filed May 22, 1998, published after the priority date, Apr. 16, 1999, of the present application, the applicant of the present invention proposes a midsole assembly having a corrugated sheet therein, which can prevent such an excessive lateral deformation of shoes.
FIGS. 5 and 6 show the midsole of the above Japanese patent application. As shown in FIGS. 5 and 6, a midsole 13 is comprised of an upper midsole 13a and lower midsoles 13b, 13b'. A corrugated sheet 14 is inserted between the upper midsole 13a and lower midsoles 13b, 13b'.
The corrugated sheet 14 extends from the heel portion to the center of the forefoot portion of a shoe and the upper midsole 13a is bonded to the upper face of the sheet 14. The lower midsoles 13b, 13b' are bonded to the heel portion and forefoot portion, respectively, of the corrugated sheet 14. The lower midsole 13b' is also attached to the upper midsole 13a. Under the lower midsoles 13b, 13b' are attached outsoles 15, 15', respectively.
Such a construction produces resistant force which prevents the heel portion of a midsole from being deformed laterally or transversely when a shoe contacts with the ground. Thereby, the transverse deformation of the heel portion of a shoe is prevented and running stability is secured.
However, in this case, when manufacturing the above-mentioned sole construction, it is necessary to bond the lower midsole 13b to the heel portion of the corrugated sheet 14 and to bond the lower midsole 13b' to the forefoot portion of the corrugated sheet 14. Furthermore, attachment of the outsole 15 to the lower midsole 13b as well as attachment of the outsole 15' to the lower midsole 13b' is required, which makes the manufacturing process rather complicated.
The main object of the present invention is to provide a sole assembly for an athletic shoe that can simplify the manufacturing process.